"As everyone knows, it's America that is the real 'hackers empire,' People's Daily, the Communist Party's flagship newspaper, wrote in a commentary.
Though China has provided scant specifics, the National Security Agency was tasked in 1997 with developing ways to attack foreign computer networks, according to recently declassified information released last month by the National Security Archive of George Washington University. One of the most successful acts of cyber-sabotage — the insertion of the Stuxnet virus into computer systems for Iran's nuclear program in 2010 — is believed to have been the work of the U.S. and Israel.
China's Defense Ministry dismissed the Pentagon report, calling it an attempt to "turn black into white and mislead international public opinion," in a statement that did not directly address the assertions about cyberspying and the overall rising capabilities of the PLA.
"In recent years, the United States vigorously developed advanced weapons and equipment and formed an offensive cyberwarfare unit. This is obvious to the international community. The United States has no right to make irresponsible remarks on China's legitimate building of its defense and military," the ministry said.
James Mulvenon, a specialist on the Chinese military and cyberwarfare at Washington, D.C.-based consultancy Defense Group Inc. scoffed at the dismissal. He tweeted: "'Groundless accusations,' eh? Wasted 100s of hours fighting in my networks."
With Beijing so far not forthcoming, often partisan forces in Washington are coalescing around the need for tougher action.
The Senate bill was introduced by a bipartisan group of senators, including Democrat Carl Levin of Michigan and Republican John McCain of Arizona. While it doesn't mention China as a specific target of sanctions, a news release on the legislation notes that "recent reports indicate that China is by far the largest source of theft attempts against U.S. companies."
"We need to call out those who are responsible for cyber theft and empower the president to hit the thieves where it hurts most — in their wallets, by blocking imports of products from companies that benefit from this theft," Levin was quoted as saying in the release.
The Senate's bipartisan approach, rising attention from the administration and public expressions of concern from the normally pro-Beijing business community illustrate how the issue has already reached critical mass, said Yu Maochun, a China scholar at the U.S. Naval Academy in Annapolis, Maryland.
"The Chinese hacking is so staggering and so significantly un-American that it has actually united major bickering and partisan sections of American society, the same way Pearl Harbor or Sept. 11 did," Yu said.
Associated Press writers Matthew Lee and Matthew Pennington contributed to this report from Washington.